Sliding contact unit for potentiometer



July 1, 1969 E A. HANSON SLIDING CONTACT UNIT FOR POTENTIOMETER FiledJune 21, 1967 V b I 'INVENTOR. 5141?; 4. H4/V50A/ 19 fi ATTOAP/VEVS'.

United States Patent Ce 3,453,584 Patented July 1, 1969 cordingly, anopen frame 12, integral with the slide, pro- 3,453,584 jects fromSLIDING CONTACT UNIT FOR POTENTIOMETER Earl A. Hanson, Ridgway, Pa.,assignor to Stackpole Carbon Company, St. Marys, Pa., a corporation ofPennsylvania Filed June 21, 1967, Ser. No. 647,661 Int. Cl. H01c /02,N12

US. Cl. 338-183 3 Claims ABSTRACT OF THE DISCLOSURE A sliding contactunit for use between parallel collector and resistor strips includes aslide provided at one side with means for moving it endwise, and an openframe projecting from the opposite side. Mounted in the frame is a wirecoil that projects laterally from it to form a bridging contact.

It is among the objects of this invention to provide a sliding contactunit which is simple in construction and quick and easy to assemble.

The preferred embodiment of the invention is illustrated in theaccompanying drawings, in which FIG. 1 is a front view of apotentiometer;

FIG. 2 is a side view thereof with part broken away; and

FIG. 3 is an enlarged cross-section taken on line HL- III of FIG. 2.

Referring to the drawings, the long rectangular housing 1 of apotentiometer may be formed from a molded plastic or other suitablerigid material. The housing preferably is made from two molded halfsections that have meeting edges extending from front to back across theend walls of the housing and lengthwise along its back or base. The halfsections are joined together in any suitable manner, such as by adhesivefor example. The front or top of the housing is provided centrally witha slot2 extending of the housing for nearly its full length. The slothas parallel sides.

Slidably mounted in the slot for movement lengthwise of the housing is arectangular slide 3 that has laterally opening grooves 4 in its oppositesides receiving the side walls of slot 2 to hold and guide the slide.The outer side of the slide is provided with a projection or knob 5 formoving the slide endwise back and forth along the slot. A metalcollector strip 7 and an electrical resistor strip 8 are mounted insidethe housing at opposite sides thereof. The collector strip is providedwith an integral terminal 9 that extends through the back of thehousing, while each end of the resistance strip is connected to a metalterminal 10 likewise extending through the back.

It is a feature of this invention that the slide is equipped withmeansfor quickly attaching a bridging contact to it so that the assembly willform a sliding contact unit. Ac-

the side of the slide opposite its actuating knob as shown in FIG. 2.Thus, the frame is entirely inside of the potentiometer housing. Theplane of the frame extends lengthwise of the slide and is parallel tothe collector and resistor strips.'The frame preferably is rectangular,with the inner side of the slide forming one side of the frame. Disposedin this frame is a wire coil 13, the axis of which is perpendicular tothe slide. The coil is held in place by a pair of projections 14integral with the frame and project-ing a short distance into theopposite ends of the coil. Most suitably, the projections are integralwith the frame and preferably are tapered toward each other as seen inFIG. 2 of the drawings to facilitate insertion of the spring in theframe. The coil projects from the opposite sides of the frame andslidingly engages both the collector strip and the resistor strip,thereby forming a bridging contact between them. The convolutions of thecoil are spaced apart sufficiently to have permitted it to be compressedaxially and inserted projections 14 and then released, whereupon it isexpanded into engagement with the frame. This manner of attaching thecoil to the slide in very simple and rapid, thereby reducing the cost ofthe potentiometer.

According to the provisions of the patent statutes, I have explained theprinciple of my invention and have illustrated and described what I nowconsider to represent its best embodiment.

I claim:

1. A sliding contact unit for use between parallel collector andresistor strips, said unit comprising a slide having ends and providedat one side with means for moving it endwise, an open frame projectingfrom the opposite side of the slide in a plane extending lengthwise ofthe slide, a straight wire coil disposed in the frame with its axisperpendicular to the slide, the coil projecting from opposite sides ofthe frame to form a bridging contact.

2. A sliding contact unit according to claim 1, in which said frame isprovided with means extending into the coil to help hold it in place.

3. A sliding contact -unit according to claim 1, in which the inside ofthe frame is provided with a pair of projections extending into theopposite ends of the coil.

References Cited UNITED STATES PATENTS 3,362,004 1/1968 Bang 200-166 X3,233,200 2/1966 Bebel 338- 2,379,047 6/ 1945 Thomas 200166 X LEWIS H.MYERS, Primary Examiner. A. T. GRIMLEY, Assistant Examiner.

US. Cl. X.R.

